A WDT tool works by moving thin needles through the coffee grounds inside the espresso basket.
The needles break up clumps and redistribute grounds from denser areas into less dense areas. This helps create a more uniform coffee bed before tamping.
Step 1: Dose the Coffee -- Grind the desired dose directly into the portafilter basket. At this stage, the coffee may contain visible clumps or uneven piles.
Step 2: Insert the WDT Needles -- Place the WDT needles into the coffee bed. For deep distribution, the needles should reach through most of the coffee bed rather than only touching the surface.
Step 3: Stir or Rotate -- Depending on the tool design, use: Manual circular motions / Vertical stirring / Rotary movement / Springback or press-and-spin action. The goal is to redistribute the grounds without aggressively compressing them.
Step 4: Level the Surface -- After WDT, gently finish the surface so the coffee bed is relatively level